The present device is related to the area of cable load binding apparatus and more particularly to such apparatus that is utilized to maintain a cable or chain in tension against a possibly shifting load.
Prior load binding or cable tightening apparatus are ordinarily constructed such that the winding spool is directly connected to a torsion spring which, in turn, is directly connected to a torsion source. Thus, to wind a cable or chain about the spool, winding force (torsion) must be transferred through the spring to the spool. When winding is accomplished through an interconnected spring and spool, the spring becomes completely wound before torque is applied directly from the source to the spool. It is undesirable to apply excessive winding force to a spring that has already been wound to its limit. Thus, it is not prudent to wind the tightening element (cable) any tigher than the equivalent capacity of the torsion spring. This is an undesirable characteristic of prior load binding appratus.
U.S. Pat. No. 3,077,791 granted to R. H. Gray on Feb. 19, 1963, discloses a pawl and ratchet mechanism for a load binding winch. This patent shows the use of the center shaft rotatably carried within a hollow spool. A spring interconnects the shaft and the spool. A ratchet wheel is interposed between the shaft and spring so when the shaft is rotated, the spring is tightened against resistance offered by the spool. Thus, the torque applied by the center shaft is transferred indirectly to the spool through the torsion spring.
U.S. Pat. No. 2,991,975 granted to M. Alexander on July 11, 1961, also discloses a load binder. Like the Gray apparatus, the Alexander binder includes a central rotatable shaft that is housed within a hollow spool and is connected to the spool through a ratchet and torsion spring. Torque is applied to the spool through the spring and interconnected central shaft.